AMEYAW, Y., et al. “Assessment of Variation in Cryptolepis Sanguinolenta (Lindl.) Schter., An Antimalaria Plant of The Family Periploceae Using Principal Component Analysis”. Asian Journal of Chemistry, vol. 19, no. 3, Mar. 2010, pp. 1809-18, https://asianpubs.org/index.php/ajchem/article/view/13746.